serial: max310x: add macro for max number of ports

Add macro to hold the maximum number of UART ports per IC/device.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Tested-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Link: https://lore.kernel.org/all/ddbc67dd-f8a3-4a6a-954a-bee49260ecab@cesnet.cz/Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-8-hugo@hugovil.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/max310x.c

@@ -30,6 +30,7 @@
 #define MAX310X_MAJOR			204
 #define MAX310X_MINOR			209
 #define MAX310X_UART_NRMAX		16
+#define MAX310X_MAX_PORTS		4 /* Maximum number of UART ports per IC. */
 
 /* MAX310X register definitions */
 #define MAX310X_RHR_REG			(0x00) /* RX FIFO */
@@ -1502,7 +1503,7 @@ static const struct max310x_if_cfg __maybe_unused max310x_spi_if_cfg = {
 static int max310x_spi_probe(struct spi_device *spi)
 {
 	const struct max310x_devtype *devtype;
-	struct regmap *regmaps[4];
+	struct regmap *regmaps[MAX310X_MAX_PORTS];
 	unsigned int i;
 	int ret;
 
@@ -1604,7 +1605,7 @@ static int max310x_i2c_probe(struct i2c_client *client)
 {
 	const struct max310x_devtype *devtype;
 	struct i2c_client *port_client;
-	struct regmap *regmaps[4];
+	struct regmap *regmaps[MAX310X_MAX_PORTS];
 	unsigned int i;
 	u8 port_addr;